Upon arrival at a distribution centre, the goods are unloaded via the boom from the ULDs and sorted for delivery to customers/retailers. The ULDs are then reloaded via the boom with other goods for transportation.
The goods are generally loaded and unloaded using a pivoting telescopic boom conveyor that can be extended telescopically and raised/lowered as required. Goods from the ULD are transferred by hand onto the boom conveyor, which then conveys the goods into the distribution centre via either a travelling conveyor belt or a set of rotating rollers.
The telescopic boom conveyor usually has a control panel at its free end, containing controls that allow an operator to control various functions of the conveyor, for example the height and extension of the conveyor, the direction of conveying operation (loading or unloading), and stopping/starting the conveyor. The controls are positioned so that they are accessible to the operator.
In order to transfer goods to and from the boom conveyor, it may be necessary for the operator to stand on a step ladder or platform. However, this is not an ideal solution as it may not be possible for the operator to adjust the height of the stepladder or platform as the height of the boom changes. Also, the use of a stepladder may give rise to safety risks.
It is known to attach an operator platform rigidly to the end of a boom conveyor, allowing an operator to stand at the correct height. This solution is satisfactory when the boom pivots through only a small angle, for example less than 5°. However, if the boom pivots through a larger angle, the floor of the platform may tilt excessively making the operator platform unstable and dangerous to use. This problem is most likely to occur if the boom is relatively short, for example less than 10 metres in length when fully extended, and is adjustable through a wide range of pivot angles.
It is also known to provide a self-levelling operator platform on an extending boom. Such an apparatus is described for example in EP2952457A1. However, the self-levelling mechanism is complex, including a pivot joint attached to an upper part of the platform and a linear actuator that is connected to a lower part of the platform. Devising a self-levelling mechanism that is simple and reliable and suitable for use on a pivoting boom conveyor is difficult.
Although it is generally desirable to provide an operator platform at the end of the conveyor, there may be occasions when it is preferable to use the conveyor without a platform. For example, if the conveyor is used to load or unload goods near to ground level it may be easier for an operator to stand on the ground so that his or her movement is not restricted by the dimensions of the platform. Therefore, it may be preferable for the platform to be removable. In this case, it is important that the operator platform can be attached and detached quickly and easily, preferably without requiring the use of tools. It is also important for safety reasons to ensure that the platform is securely and correctly attached to the conveyor before the conveyor is raised to an elevated working position.
Finally, it is important that the operator platform allows unobstructed access to the operating controls provided at the end of the conveyor.